The ZnTiO3 material was synthesized by sol–gel method with the assistance of ethanol as solvent. The oxidative polymerization method was used to synthesize polycarbazole (PCz). The ball milling technique was employed to synthesize the mechanically composited nanoparticles—ZnTiO3/PCz nanocomposite. The synthesized composites were analysed using powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectrum (XPS), UV–Vis absorption spectrum (UV–Vis), scanning electron microscope (SEM), and high-resolution transmission electron microscope (HRTEM). The degradation of crystal violet (CV) in water under visible-light irradiation was used to assess the photocatalytic behaviour of the synthesized catalyst. The result shows that the ZnTiO3/PCz composites exhibit greater photocatalytic activity than other materials. Polycarbazole in composite material acts as an electron reservoir, actively trapping the photogenerated electrons which considerably lowers the probability of recombination and increases the degrading effect of the catalyst.